Chemical carcinogenesis: persistence of bound forms of 2-fluorenylacetamide

The persistent binding of metabolites of hepatic carcinogen, 2-fluorenylacetamide, to glycogen and to DNA in a new population of liver cells, hyperplastic nodules, and to glycogen in liver cancer cells weeks to months after the carcinogen was removed from the animals' diet is indicated by spectrophotometric, chromatographic, and mass spectrographic data. This persistence of binding does not appear to occur in the nonhyperplastic or nonneoplastic liver surrounding the nodules or the cancer.     

Effects of environmental factors on plant functional traits across different plant life forms in a temperate forest ecosystem

New Forests - Plant functional traits have been shown to vary with environmental conditions. However, we lack empirical data on how plant functional traits of different plant life forms respond to...     

The ecological sustainability of tropical forest management: evaluation of the national forest management standards of Costa Rica and Nicaragua, with emphasis on the need for adaptive management

From a conceptual point of view, national forest management standards in Latin American countries have progressed significantly in recent years. Examples include the Costa Rican Standards and Procedures for Sustainable Forest Management and Certification, developed by the National Commission for Forest Certification and in Nicaragua, the National Institute of Forestry proposal of principles, criteria and indicators for sustainable forest management. In line with general approaches worldwide, these national standards primarily focus on the fulfillment of sound forest practice. There is comparatively little emphasis on the assessment of management outcomes or changes in key components of the eco- and social-systems that result from management impacts. Essentially, there is little emphasis on adaptive management, though arguments that management cannot be sustainable if it is not adaptive are persuasive. This study sought to contribute to the development of standards that include elements for adaptive management that define, communicate and evaluate sustainable forest management in Costa Rica and Nicaragua. Elements from the national standards and the CIFOR generic C&I template (predominantly focused on forest management outcomes) were used as a starting point. The basic research process consisted of three phases of evaluation (in-office, desk and field). The evaluations were carried out by multidisciplinary, international groups of experts in forest ecology, management and policy. This study demonstrated the value of forums and workshops that facilitate exchange between forest scientists and policymakers; the innovation and application of a practical, applicable and scientifically based methodology for developing national level C&I; and acceptance of this methodology by key players in the fields of forest management and policy. These experiences and the resulting proposals of C&I for the evaluation of ecologically sustainable forest management are expected to be used as points of reference for future development of forest policy in Costa Rica and Nicaragua, and to contribute to the overall understanding of C&I development processes in the region.     

中国竹林可持续经营认证的必要性和可行性研究

通过文献研究、野外调查和专家研讨和咨询等研究方法,从中国竹林经营现状和世界森林可持续经营认证(简称森林认证)发展趋势入手,对中国开展竹林可持续经营认证的必要性和可行性进行了研究。结果表明,竹林快速生长和更新特性使竹林具有一定的可持续经营性,同时,中国现有的竹林经营技术实践在一定程度上满足了可持续经营的要求。但是,中国有较大面积的人工经营天然次生竹林,长期高强度集约经营对整个竹林生态系统的复杂性和完整性也造成了很大影响,由此引发了很多集约经营的生产性竹林水土流失、地力下降、生物多样性丧失、严重病虫害频发等生态问题,威胁着竹林可持续经营。根据我们的研究,按照目前森林认证发展趋势,竹林可持续经营认证作为促进竹林可持续经营的市场激励手段之一,是值得研究和尝试的。在中国开展绩效性的竹林可持续经营认证,不但有利于中国竹产品在国际贸易中克服绿色贸易壁垒,保持竞争优势,也有利于引导和促进中国竹林的可持续经营实践。总体上竹林认证是必要的。但在可行性方面面临一些问题和挑战。鉴于竹林本身的生物学和生态学特性、竹林经营的技术特点、竹林产品为非木质林产品的特殊性以及我国较为普遍的分户经营特点,可开展小范围试点研究,解决如何开展中小农户的联合认证问题和认证成本过高的问题,同时确保中小农户的利益和竹产品的公平贸易,为进一步的推广行动提供技术支持。在研究和推进竹林可持续经营认证的过程中,要充分考虑与中国现有竹林经营的行业标准和经营实践相衔接和适应。除了要充分利用国内外现有森林认证的理论、技术和经验,还必须充分与竹产业的生产、教学和研究人员进行磋商,充分利用现有竹业经营和开发的经验和技术。以期通过可持续经营认证,保护中国竹产品的国际贸易竞争力,同时积极引导和促进中国竹林可持续经营实践的发展和行业标准的制定。     

Natural biological control of <Emphasis Type="Italic">Halyomorpha halys</Emphasis> by native egg parasitoids: a multi-year survey in northern Delaware

Halyomorpha halys (Stål) is a highly polyphagous plant pest native to eastern Asia. Since its accidental introduction to the USA in the mid-1990s, it has spread across North America and caused serious economic damages. Chemical control has been a widely applied management strategy which is not sustainable on a long-term basis. A nine-year survey using sentinel and naturally laid H. halys was conducted to investigate the extent of natural biological control by parasitoids in managed and non-managed landscapes in northern Delaware, USA. Naturally laid egg masses of native pentatomids were collected to compare the resident parasitoid complex to the one attacking H. halys eggs. Mean parasitism rates of sentinel eggs were below 6% in any given year of the survey with a grand mean of 1.79%. Parasitism of naturally laid H. halys eggs was higher than that of sentinel eggs, but there was no significant difference in parasitism between years and the grand mean was 4.31%. Parasitoid species richness on sentinel and naturally laid H. halys eggs was similar but both were lower than the richness on native pentatomid eggs. H. halys eggs were parasitized by eight species in the genera Anastatus, Trissolcus, Telenomus, and Ooencyrtus. The level of parasitism by native egg parasitoids is insufficient to provide long-term control of H. halys. Trissolcus japonicus (Ashmead), an Asian egg parasitoid that has been recovered in the USA in several locations since 2014, may be the most promising candidate for long-term biological control of H. halys.     

Effects of oral potassium supplementation on acid-base status and plasma ion concentrations of horses during endurance exercise

OBJECTIVE: To compare effects of oral supplementation with an experimental potassium-free sodium-abundant electrolyte mixture (EM-K) with that of oral supplementation with commercial potassium-rich mixtures (EM+K) on acid-base status and plasma ion concentrations in horses during an 80-km endurance ride. ANIMALS: 46 healthy horses. PROCEDURE: Blood samples were collected before the ride; at 21-, 37-, 56-, and 80-km inspection points; and during recovery (ie, 30-minute period after the ride). Consumed electrolytes were recorded. Blood was analyzed for pH, PvCO2, and Hct, and plasma was analyzed for Na+, K+, Cl-, Ca2+, Mg2+, lactate, albumin, phosphate, and total protein concentrations. Plasma concentrations of H+ and HCO3-, the strong ion difference (SID), and osmolarity were calculated. RESULTS: 34 (17 EM-K and 17 EM+K treated) horses finished the ride. Potassium intake was 33 g less and Na+ intake was 36 g greater for EM-K-treated horses, compared with EM+K-treated horses. With increasing distance, plasma osmolarity; H+, Na+, K+, Mg2+, phosphate, lactate, total protein, and albumin concentrations; and PvCO2 and Hct were increased in all horses. Plasma HCO3-, Ca2+, and Cl- concentrations were decreased. Plasma H+ concentration was significantly lower in EM-K-treated horses, compared with EM+K-treated horses. Plasma K+ concentrations at the 80-km inspection point and during recovery were significantly less in EM-K-treated horses, compared with EM+K-treated horses. CONCLUSIONS AND CLINICAL RELEVANCE: Increases in plasma H+ and K+ concentrations in this endurance ride were moderate and unlikely to contribute to signs of muscle fatigue and hyperexcitability in horses.     

Apium graveolens PI 181714 is a source of resistance to Fusarium oxysporum f. sp. apii race 4 in celery (A. graveolens var. dulce)

Celery has little genetic diversity and is highly susceptible to the new fungal pathogen Fusarium oxysporum f. sp. apii (Foa) race 4. After screening an Apium graveolens germplasm collection for resistance to Foa race 4, we crossed celery cv. 'Challenger', which is Foa race 2-resistant but Foa race 4-susceptible and A. graveolens PI 181714, which is Foa races 2- and 4-resistant but non-celery type. After selfing F₁s, we screened the F₁S₁ for race 4-resistance and celery-type and then selfed selected F₁S₁. Greenhouse and field trials indicate that three selected F₁S₂ families (76–8-4, 76–8-27 and 76–8-36) are suitable as germplasm for celery breeders for resistance to Foa race 4. A F1S3 76–8–36-124 is either fixed or nearly so for resistance to Foa races 4 and 2. Furthermore, quantitative PCR indicates that PI 181714 is resistant, rather than tolerant, to Foa races 4 and 2, and that this resistance has been introgressed into F1S3 76–8–36-124.     

Intra-varietal variation for in vitro plant regeneration in the genus Trifolium

Summary Seedlings of Trifolium repens showed considerable variation with regard to the morphology and growth of their calli, and their ability for in vitro differentiation of shoots. One of the lines selected for regeneration in primary callus cultures also showed shoot formation from protoplasts. Somatic embryogenesis in callus cultures of T. pratense and T. arvense occurred only in selected seedling lines. This paper highlights the importance of screening a large number of plants within a cultivar of outbreeding species to achieve reproducible plant regeneration from tissue culture.     

Comparison of the α-amylase inhibitor-1 from common bean (Phaseolus vulgaris) varieties and transgenic expression in other legumes--post-translational modifications and immunogenicity

The seeds of peas (Pisum sativum) and chickpeas (Cicer arietinum) expressing a gene for α-amylase inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are protected from damage by old world bruchids (pea and cowpea weevils). Here, we used electrospray ionization time-of-flight mass spectrometry to compare the post-translational modifications of αAI from transgenic sources with the processed forms of the protein from several bean varieties. All sources showed microheterogeneity with differences in the relative abundance of particular variants due to differences in the frequency of addition of glycans, variable processing of glycans, and differences of C-terminal exopeptidase activity. The structural variation among the transgenics was generally within the range of the bean varieties. Previously, mice showed allergic reactions following ingestion of transgenic pea αAI but not bean αAI. Here, only minor differences were observed following intraperitoneal sensitization. Both of the transgenic pea and bean forms of αAI elicited Th1 and Th2 antibody isotype responses, suggesting that both proteins are immunogenic and could potentially be allergenic.